76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* A generic stack depot implementation
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*
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* Author: Alexander Potapenko <glider@google.com>
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* Copyright (C) 2016 Google, Inc.
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*
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* Based on code by Dmitry Chernenkov.
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*/
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#ifndef _LINUX_STACKDEPOT_H
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#define _LINUX_STACKDEPOT_H
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#include <linux/gfp.h>
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typedef u32 depot_stack_handle_t;
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/*
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* Number of bits in the handle that stack depot doesn't use. Users may store
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* information in them.
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*/
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#define STACK_DEPOT_EXTRA_BITS 5
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depot_stack_handle_t __stack_depot_save(unsigned long *entries,
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unsigned int nr_entries,
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unsigned int extra_bits,
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gfp_t gfp_flags, bool can_alloc);
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/*
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* Every user of stack depot has to call stack_depot_init() during its own init
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* when it's decided that it will be calling stack_depot_save() later. This is
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* recommended for e.g. modules initialized later in the boot process, when
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* slab_is_available() is true.
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*
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* The alternative is to select STACKDEPOT_ALWAYS_INIT to have stack depot
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* enabled as part of mm_init(), for subsystems where it's known at compile time
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* that stack depot will be used.
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*
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* Another alternative is to call stack_depot_want_early_init(), when the
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* decision to use stack depot is taken e.g. when evaluating kernel boot
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* parameters, which precedes the enablement point in mm_init().
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*
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* stack_depot_init() and stack_depot_want_early_init() can be called regardless
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* of CONFIG_STACKDEPOT and are no-op when disabled. The actual save/fetch/print
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* functions should only be called from code that makes sure CONFIG_STACKDEPOT
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* is enabled.
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*/
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#ifdef CONFIG_STACKDEPOT
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int stack_depot_init(void);
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void __init stack_depot_want_early_init(void);
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/* This is supposed to be called only from mm_init() */
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int __init stack_depot_early_init(void);
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#else
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static inline int stack_depot_init(void) { return 0; }
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static inline void stack_depot_want_early_init(void) { }
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static inline int stack_depot_early_init(void) { return 0; }
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#endif
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depot_stack_handle_t stack_depot_save(unsigned long *entries,
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unsigned int nr_entries, gfp_t gfp_flags);
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unsigned int stack_depot_fetch(depot_stack_handle_t handle,
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unsigned long **entries);
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unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle);
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int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
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int spaces);
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void stack_depot_print(depot_stack_handle_t stack);
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#endif
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